Macro for adding blank cells based on previous data

Weekly we receive a list of email addresses of people who have opened our e-newsletter. Obviously this list changes a little every week. Right now we are pasting this list into a new column in Excel, then manually adding spaces where necessary so that like email addresses line up across the row (so we can track over time who is reading it.)

See example

Is it possible to write a macro that looks back to the master list column, then adds the blank cells in the new column where necessary to accomplish this?

Here’s the hitch: from our website people can opt in to the newsletter, so occasionally a new name will appear in the weekly list that we don't yet have in the master list, which I assume will have to be added manually.

Or is this perhaps a project better suited to Access?

Thank you so much.